A fuel cell is an electricity-generating system for directly converting chemical energy into electric energy through a chemical reaction between hydrogen or hydrogen contained in hydrocarbon materials such as methanol or ethanol with an oxidizing agent.
Representative examples of the fuel cell include a polymer electrolyte membrane fuel cell (PEMFC) and a direct oxidation fuel cell. A direct oxidation fuel cell using methanol as fuel is called a direct methanol fuel cell (DMFC).
In general, the polymer electrolyte membrane fuel cell is advantageous in high energy density and high output. To produce hydrogen from the fuel, a fuel reformer for reforming methane, methanol, natural gas, etc. is necessary.
Fuel reforming may be classified into steam reforming, partial oxidation reforming and autothermal reforming depending on the reforming method. Although steam reforming exhibits high hydrogen production efficiency, response is slow because the associated reaction is endothermic and heat has to be supplied. Partial oxidation (PDX) reforming exhibits fast response because the associated reaction is exothermic and heat supply is unnecessary, but hydrogen yield is not high. Autothermal reforming (ATR) has the advantages of the above-described two reforming methods: less energy input and fast response.
In autothermal reforming, a catalyst is used to reform fuel gas. In general, the catalyst is in powder form and has spherical, cylindrical or pellet shape depending on reaction condition and state. However, in order to process the catalyst into the desired shape, an additive such as a binder is necessary. In addition, the existing catalyst has the problems of low specific surface area and pressure difference.
Although a monolithic catalyst has been developed to improve the problems, reactivity is low due to insufficient gas mixing and fast gas flow in the monolith.